Field of the Invention

The present invention relates to barriers and particularly to barriers for controllably blocking access to and from an enclosure, a venue or other restricted space vehicle access barriers or livestock and crowd control gates. The invention particularly relates to a barrier control system for the electronic actuation of an access control barrier utilising remote means, barrier movement control, remote monitoring features, the powering of said barrier and the detection of interference with the barrier and deterrent means to prevent or minimise further interference.

Background to the Invention

The access control barriers utilising the control system of the invention have applications in a number of distinct technical and commercial areas, each of which having its own peculiar drawbacks and problems to be addressed, some of which are common across these distinct areas. The present invention seeks to alleviate significant disadvantages in many of these areas, which are discussed in general terms below. Reference to one area should not be taken as limiting the application or utility of the invention in another.

As will readily be appreciated from the patent literature, there are many different approaches taken to solving some of the technical difficulties associated with livestock control, crowd control, vehicle access control and controlled or timed access of vehicles across or through a passageway, particularly at railway intersections. Each area presents specific concerns, however, many aspects are common and will be addressed hereinafter.

The prior art is replete with different solutions to these problems, all with varying degrees of success. The present invention is directed to the control of any access barrier, however, for the purpose of clarity, the description hereunder is directed to barriers or gates where the primary control element or boom moves in a vertical plane.

A discussion of prior art barriers and their respective shortcomings is presented in Applicant's co-pending UK Patent Application Nos. 135703.9 & 1305706.2 which is incorporated herein by reference.

Although much of the description which follows is directed to the control of livestock, the invention is not so limited and the skilled reader will readily appreciate the application of the inventive features to crowd control, vehicle access control and railway crossings. Much of the discussion in the prior art is directed to the structure and configuration of livestock, crowd control, vehicle access control and railway crossing barriers and how they can achieve particular aims. There is a dearth of discussion regarding effective control of movement of such barriers or how to most efficiently power barriers in remote, inaccessible locations, for example. Conversely, there is a wealth of teaching towards energiser circuits for electric fences and their extension to barrier gates, however, little is directed to a standalone, self-powered access control barriers having interference deterrent means or to the advantages conferred thereby.

The problems associated with constraining livestock within a field or paddock are very well established. In the normal enclosure, a fence is provided around the periphery of the enclosure and at least one gate or access point for vehicles or to allow for the ingress and egress of livestock is provided. To the uninitiated the need for a driver or farmhand to physically open the gate each time a vehicle passes through would seem to be a minor burden, however, amongst livestock keepers, the problems are well appreciated. Included amongst these considerations are exposure to livestock during the time taken for the vehicle to pass through the gate, where the enclosure exists onto a public road, the time a farm vehicle is unmanned or blocking traffic and, increasingly more importantly, to address concerns over bio-security. Where there are controllable factors regarding cross-contamination, any means which decreases the risk of spreading disease or introducing new or untraceable components should be embraced. If an operator or farm worker does not have to get in and out of a vehicle repeatedly (particularly at the point of entry to an enclosure), the risk of carrying water, mud or detritus from one location to another is lessened. Additionally, the accumulation of detritus within the vehicle is best avoided particularly as it can create an unpleasant working environment.

One of the disadvantages not fully appreciated in any of the prior art referenced in co-pending UK Patent Application Nos. 1305703.9 & 1305706.2 is that many of the barrier/confinement means provided generate a fear response in the subject livestock. Clearly when a barrier is removed, the fear response to the barrier is removed. Conversely, where a shock comes from an unknown source, such as a mat, the fear response becomes associated with the space itself, so that once power is removed, the fear response remains. Thus, it is considered that a visual barrier associated with a physical disincentive (delivered as an electric shock) provides the ideal combination, so that when the visual barrier is removed, so too is the disincentive to cross the access/fence void.

Limited overhead clearance is also a consideration with rising boom barriers, particularly where there is a wide passageway span. Even where a wide span is protected by a pair of opposed barrier booms, there remain situations where overhead clearance remains problematic. As the standard rising boom moves upwardly in a constrained vertical arc, there is an increased chance of collision with surrounding objects. Within buildings, the height reached is of primary consideration as the available height dictates the maximum span of a single barrier. Trees, hedges and overhead cables are of concern when the barrier is provided in an outside setting. Additionally, there are vehicular considerations, for example, with agricultural devices where a front end loader might encroach the space over a boom as the vehicle approaches the barrier.

Of the rising boom type barrier constructions, there is known to be a significant power overhead to raise and lower the barrier boom arm. This overhead is an additional reason why in remote locations some rail crossings are left unguarded, as to provide power would involve significant additional expense. Whereas with livestock enclosures, any electrically conductive elements may be connected to an existing electric fence or powered by an independent excitation circuit, it remains the power demand to raise and lower a gate that is prohibitive. For safety and due to the general remoteness of such barriers, most are operated via a 12 volt battery pack usually trickle-charged via a solar panel. There has been a notable rise in thefts of both battery packs and solar panels due to their intrinsic value and utility for other applications. Increasingly, where heavy power cables or an array of signalling or data trunking is provided to a barrier, theft of cabling for metal recycling has also become a significant problem.

There is also an often ignored problem with automatically shutting gates (of deflecting or rising types) which is to do with the length of time taken to finally close the gate and the speed at which the free end of the gate or barrier boom moves. Where the shutting mechanism (or cycling period) is too slow, a curious animal may have sufficient time to escape, a pedestrian may duck under a descending barrier arm or a driver may attempt to follow a preceding vehicle without authorisation or allowing sufficient time to clear. Additionally, if the cycling or raising and lowering a boom arm is too long, the time advantage of automating the closing action may be substantially lost. Where the shutting mechanism is too fast, there is a risk of incurring damage or injury by striking a vehicle, an animal or a person. What is so rarely appreciated is the tip speed of a closing barrier boom, which when approaching from above will not be seen prior to a strike.

It is also know, particularly where animals congregate around a gate or where feeding is anticipated, there is a risk of a barrier being forced unless electric shock is provided as a disincentive. Arrangements or installations for constraining larger animals require reinforced or very sturdy build quality and anchor points and are therefor considered permanent installations. Where occasional access control is required or the access passageway is not always in the same place, such solutions are not appropriate. There is thus also a requirement for a substantially mobile livestock barrier having the levels of security and functionality normally provided by permanent installations.

There is an additional requirement regarding the monitoring of ingress and egress which is not normally afforded by standard barrier installations. A record of the number of times a barrier arm is elevated is most easily kept using a manual incrementing counter, however, this record is only accessible by physically reading the counter display. Where security is an issue, it is often useful to log the period between ingress and egress. This is a simple matter where only one person is gaining access to the secure area and where personal identification is used to gain access, individuals are easily distinguished. Video surveillance is normally disassociated with the operation of a barrier, however, as will be discussed hereinafter, certain advantages be achieved where operations are unified.

It is an object of present invention to seek to alleviate the above disadvantages and to provide improved control of access control barriers. It is also an object of the present invention to seek to alleviate the above disadvantages and to provide an improved barrier gate for vehicle access and livestock or crowd control.

It is also an object of the present invention to reduce the incidence of power pack thefts and to decrease the resale value of the components used. It is a further object of the present invention to provide enhanced safety and security features to an access control barrier.

It is a yet further object of the present invention to provide an improved barrier activation and control circuit. As additional objects of the invention, there is provided drive mechanisms and deflection correction mechanisms for a barrier; improved access control and remote activation; and a regulated energising circuit for detecting interference and having controlled delivery of warnings and deterrents (including shock voltages).

Summary of the Invention

Accordingly, the present invention provides an access control barrier of the type used for livestock control and for vehicle access and crowd control having a barrier boom arm rotatably driven at one end around a horizontal pivot axis mounted on a support post and movable between an upright open position and a horizontal closed position, the control system comprising: a plurality of conductors connected to or located on the boom arm of a barrier; interference detection means, being responsive to animal, vehicle or human contact of one or more of the conductors ; warning delivery means to disincentivise continued contact; and control means for regulating delivery of warnings, in which the interference detection means determines the nature and duration of interference arising from contact with one or more of the conductors and triggers a response via the control means to deliver a warning against continued interference with the barrier boom arm.

Conveniently, the warning delivery means is selected from audio output means, light output means and electric shock output means.

Advantageously, the control means regulates the parameters of amplitude, frequency and timing of the warning delivery means. Prefereably, the parameters controlled result in a progressively more uncomfortable experience for the driver of a vehicle or an animal or human interfering with or remaining adjacent the barrier, whereby the frequency, amplitude and/or timed pulses of sound, light or electric shock delivered achieve the desired disincentive to continued interference.

Ideally, the warning delivery means comprises a shock voltage delivery means associated with shock voltage accumulators to generate a stored charge, wherein shock voltage delivery is initiated, after it is determined by the interference detection means that the barrier boom is being touched by an animal or human, to deliver from the stored charge a first level shock voltage which increases in amplitude in accordance with a predetermined set of parameters including timing and duration.

Advantageously, the control means determines the shock parameters according to the nature and duration of the interference detected and includes means for triggering timed pulses of shock voltages to achieve the desired disincentive to continued interference.

Preferably, shock voltage accumulators are charged or "topped-up" only when a shock response is required.

Conveniently, by minimizing the stored charge and by utilising detection pulses via the interference detection means, the power consumption of the energizing circuit is significantly below that previously achieved.

Advantageously, continued interference activates an alarm state which triggers an additional response selected from, sounding an alarm, illuminating a light source, initiating movement of the barrier boom, commencing video monitoring and transmitting a signal identifying a fault via radio transmission, mobile telephone network or data link.

In such instances where electrification of a barrier is used or where sensors are provided to indicate physical interference with a barrier, interference detection is available through the barrier energiser detection circuitry which can in turn be monitored by the barrier control circuit CPU. There are three levels of interference detection/monitoring. From the energiser circuit, any sudden discharges (signifying an earthing of the electrified portion of the barrier) are recorded as interference, which if repeated within in a short time span will indicate tampering or a serious fault. Where the barrier has been knocked away from a set position, where it has been locked by the drive motor, the deflection mechanism associated with the drive motor or gear has a detection sensor associated therewith which provides data to the CPU. Additionally, within the barrier drive motor circuitry, there is provided a power surge detection unit which again can be monitored by the barrier CPU.

In a second aspect, the invention provides a control system which is operably connected to a drive mechanism for an access control barrier, the drive mechanism comprising: an electronically controlled drive motor constrained within a housing secured to the support post positioned at one side of a passageway through which access is to be regulated and coupled to a power source, the drive motor operably rotating a drive shaft which defines the horizontal pivot axis about which the boom arm rotates. Advantageously, the control system includes an electronic controller providing power to the drive motor is configured to ensure the rotation of the drive shaft is regulated to provide the required parameters of access time and its selected use, whilst minimizing the load on the power source.

Preferably, the power source comprises a low-wattage (Ampere-hour) battery connected to a recharging circuit which is fed from a renewable source.

In one construction, the renewable source is a solar array which includes means for tracking the sun's path throughout the day. Optionally, the renewable source comprises a micro wind turbine rotatably mounted to a pole extending from the support post or a pole adjacent thereto and having a wind vane to direct the turbine into the wind.

In a preferred arrangement, the barrier boom arm comprises first and second arm elements, the second arm element being rotatably attached to the first arm element by a drive coupling and driven to rotate with respect thereto by a transmission means, so that the arm elements move synchronously between the closed position where the arms are fully extended horizontally across the access passageway and the open position where the arms are folded together in a vertical overlying position.

Advantageously, the barrier is automatically actuated by means selected from one or more of the followings: automatic actuation means which closes a normally open gate in response to an approaching train and opens again as the train recedes; card or coin fed mechanisms or vehicle number place recognition systems generating an actuation signal to the drive mechanism of the barrier; remote control actuation means either by a manually operated transmitter, including a key-fob transmitter, a transmitter mounted within a vehicle or a device utilizing a mobile data network or implemented via an application program (app) on a smartphone; an audible signal producing a recognised waveform, such as a vehicle horn; and a crowd control barrier actuation means to limit or regulate access, particularly where access is granted based on personal identity or timed activation. Conveniently, the barrier includes an access monitoring means which in its simplest form records the period between actuations of the barrier or where the barrier is used to restrict access, an alarm state is set if a period between ingress and egress is exceeded.

The first and second arm elements ideally each comprise upper and lower tubes having conductive elements adapted to carry a pulse voltage generated by an excitation circuit. The tubes are optionally provided with strips of conducting material or the tubes themselves are formed from a conducting carbon fibre composite, aluminum, steel or other suitable conducting material, electrically isolated from the drive mechanism, housing and support post. Additional shock voltage conductors can be suspended from the lower tubes of the first and second arm elements. The excitation circuit is disconnected from the conductors when the barrier boom is elevated from the horizontal closed position.

The barrier drive mechanism includes a spring to balance the weight of the boom in the closed position. As the barrier opening motion commences there is a high degree of self-balancing within the folding action that is not evident in fixed boom barriers.

Advantageously, the barrier is automatically actuated by a plurality of mechanisms according to the barrier's use. For example, where the barrier is associated with a railway crossing, automatic actuation closes a normally open gate in response to an approaching train and opens again as the train recedes. The mechanisms by which such activation is initiated is well known from the prior art and will not be examined here in depth. Suffice it to say that in isolated rural areas monitoring of railway crossings, replacement of manually operated gates and provision of barriers at open crossings is of great importance.

At vehicle toll booths and vehicle access barriers, card, coin and vehicle number place recognition systems may all be used to provide an actuation signal to the drive mechanism of the barrier. One system not currently in use is where the barrier is automatically actuated in response to an audible signal having a recognized waveform, such as a vehicle horn. Remote control actuation may also be facilitated either by a manually operated transmitter, such as a key-fob transmitter or by mounting a transmitter within the vehicle itself. Each key- fob or vehicle mounted actuating unit can be uniquely coded, so as to identify or maintain a record of who activated the barrier. Access can also be regulated to within specified hours.

In gated communities or in estate management, where there may be valuable artifacts, artworks or collections, including of exotic animal and plant species, issues of security, bio-security and traceability are of increasing importance. Where animals are vulnerable to imported disease or where legislation dictates the destruction of a herd upon a single reported incidence of an infectious disease, restricting and monitoring access to animals provides for better disease control, material for use as evidence and traceability of stock.

Where animals are kept for breeding or are destined to enter the food chain, an accurate record of origin, together with proven farm procedures, all go towards meeting requirements. Whether for plant or animal species, any means which decreases the risk of spreading disease or of introducing new or untraceable components should be embraced. Access records, whether simple recording of barrier actuations to personnel identification of individuals entering and exiting a property, a building or an enclosure and video monitoring, all provide enhancements to community, estate or building management, property and personal security, theft prevention, article tracking and plant or animal traceability and disease control.

Similar mechanisms may be used at a crowd control barrier to limit or regulate access, particularly where access is granted based on personal identity, however, where crowd control or direction of queues is of concern, activation may be timed.

In arrangements and systems where power consumption is less of a priority or the monitoring of ingress and egress is of primary importance, the barrier optionally includes an access monitoring means which in its simplest form records the period between actuations of the barrier. Where the barrier is used to restrict access, an alarm station may be set if a period between ingress and egress is exceeded. Timing the difference between ingress and egress is exceptionally useful in many situations ranging from attendance time on site, access time to secure records or archives, over-staying for time-limited events and for reasons of safety. If a construction or quarry worker has gone on site for a fixed period activity and has not timely returned, the worker may have come to harm or be incapacitated. By setting a time between normal actuations of a barrier, an alarm condition may be established whereby a site manager, foreman or other party may be notified of a potential emergency.

Video monitoring systems may also be linked to the barrier so that a visual record of activation or disturbance of the barrier may be made. In some locations, prosecutions based on video evidence, for example, for "jumping" rail crossings, may be initiated.

Wireless transmission of data from a barrier advantageously provides a number of potential enhanced features. A record of barrier activations or interferences (depending on the nature of the activations) or event recording by a central processing unit (CPU) and associated memory can provide useful management and maintenance data. By augmenting the control circuit with wireless transmission, including by mobile telephony, advance security and monitoring becomes available. Still images and video monitoring from a remote location is easily achievable with a relatively low power consumption overhead. Data, including image and video data, may be transmitted to and recorded by a mobile (cellular) telephone, a central office computer or video recorder or a screen provided within a site office or the cab of a maintenance or security personnel vehicle.

Vehicle number plate recognition systems may also be used with the barrier to assist in video monitoring.

In a third aspect of the invention, the control system is operably connected to an access control barrier, the barrier comprising: a barrier boom arm mounted for rotation with respect to a support post, the boom arm being movable between a closed blocking position and an open access position in response to a signal, in which the boom arm comprises a first arm element, rotatably driven at one end around a horizontal pivot axis mounted on said support post, and a second arm element pivotally coupled to the other end of the first arm and driven to rotate with respect thereto during the transition between said open and closed positions. Advantageously, there is provided at or adjacent the support post a drive motor having a drive shaft adapted to rotate the first arm element around said horizontal pivot axis, the second arm element being secured to the first arm element by a drive coupling to which rotational movement is conveyed from the drive shaft via a transmission means. The barrier boom arm comprises a folding arrangement of the first arm element and the second arm element which is driven on a reduced ratio gear through approximately 180° with respect to the first arm element, so that the arm elements substantially overlie one another in the open position and are in extended longitudinal coaxial relationship in said closed position. Preferably, each barrier arm element comprises a pair of elongate members held in fixed apart relationship, said members being adapted to house the transmission means which, ideally, comprises a closed loop drive selected from nylon, wire, toothed belt or chain.

Conveniently, the transmission means translates rotational motion of the first arm element at the drive shaft to rotation of the second arm element via the drive coupling so that the second arm element moves simultaneously with the first arm but has a minimal locus of movement.

Ideally, the drive motor includes electronic control to decelerate the rotational movement of the drive shaft as the barrier arm approaches its closed/blocking position and feedback torque control is provided to sense an impact and to reverse momentarily the rotational movement.

Conveniently, the drive coupling includes stops to prevent over-rotation of the barrier arm elements. Preferably, the drive motor has a rotational limit of 90° to carry the first arm element between its horizontal closed position and its vertical open position.

Whilst the drive motor is stated as having a 90° range of movement, the resultant movement on the first arm element is not so fixed. Where the boom arm is forced, usually by a downwardly force applied to a closed horizontal boom, means are provided, as described in more detail hereinbelow, to allow the arm to move beyond its normal limits. The means is facilitated by a mechanism disposed within or adjacent the drive motor and may be selected from a clutch element, a shear pin and a system of springs and/or pivotal mounts to disengage the drive motor from the boom arm. Thus, advantageously the gate arm can be moved below the horizontal where there is a force applied which would otherwise potentially damage the boom arm. Similarly, if the boom arm is forced upwardly, the mechanism will allow for this movement without incurring damage to the arm or the drive motor. The mechanism is self-correcting so that once the force is removed and the drive motor is re-engaged, the horizontal closed position and upright open position are re-established.

A self-righting deflection mechanism is also provided for instances where there is an impact primarily in a horizontal plane with the barrier of sufficient force to potentially break the boom arm elements. Ideally, the mechanism includes a spring or spring-loaded element biased to return the boom to its central position across the access passageway.

By using a 2: 1 gear ratio, the transmission means translates the 90° rotational movement of the first element to 180° relative rotational movement of the second arm element. The translation is linear, smooth and, from an external perspective, the second arm element appears to move only through 90°, that is between its vertical orientation, aligned with or overlying the first element, to its horizontal orientation, coaxial with the first arm element, in the closed position.

The invention yet further provides a control system which includes a remote computer device onto which is loaded computer-readable instructions which, when executed by a processor, cause a computing device to perform a set of actions to effect actuation of a barrier in accordance with the invention.

There is further provided means to effect communication with a communication device including a processor and associated memory for storing software including a smartphone application program (app).

Conveniently, the software or app is downloadable from the Internet.

Brief Description of the Drawings

The present invention will now be described more particularly with reference to the accompanying drawings which show, by way of example only, an access barrier, drive mechanism and control system therefor in accordance with the invention. In the drawings:

Figure 1 is a front elevation of a barrier having a first arm element and a second arm element pivotally attached thereto in a closed position;

Figure 2 is a front elevation of a pair of opposed barriers positioned to provide restricted access through a passageway having an extended span;

Figures 3a to 3e are front elevations of variations of a barrier arm drive mechanism for rotating a horizontally disposed drive shaft;

Figures 4a to 4d are detailed illustration of the transmission means to provide synchronous movement of the arm elements between their open and closed positions and illustrations of the relative positions of the arm elements as they move between the open and closed positions;

Figures 5a to 5f are an alternative drive mechanism for a barrier of the invention having a self-righting mechanism for correcting deflections in a vertical plane and first and second variants of a self-righting mechanism for correcting deflections in a horizontal plane; Figures 6a to 6d are a block circuit diagram and component circuit diagrams illustrating the primary control system circuits associated with the drive control circuit, the recharging source circuit, the energising circuit associated with interference detection and deterrent delivery, and a user interface or programming screen and a series of waveform responses, respectively;

Figure 7a is a first series of screenshots of a user interface or programming touch- sensitive screen connectable to the drive control circuit; and

Figure 7b is a second series of screenshots of the interface illustrating functions and information available to the user or programmer.

Detailed Description of the Drawings

Referring to the drawings and initially to Figure 1 , the vehicle access and livestock or crowd control barrier governed by the control system of the invention comprises a barrier boom 1 pivotally mounted on a support post 2. A base support 3 is anchored to the ground and provides an earthing point 4, where necessary. A vehicle detection sensor 5 is optionally provided on the support post to ensure the gate does not close on a vehicle remaining in an access passageway. In the construction illustrated in Figure 1, a drive motor 6 is arranged to drive a horizontally disposed drive shaft 7. The shaft 7 is coupled to a drive sprocket 9 connected to a primary pivot disc 10 which defines the pivot axis A about which the barrier boom 1 rotates. A control system including circuit boards for an energiser 12 and for a motor controller 13, together with a battery 15, the drive motor 6, the horizontally disposed drive shaft 7 and associated components are positioned within an enclosure 17 mounted on the support post 2.

In the preferred construction of the invention, the length of the support post 2 is adjustable so as to provide barrier installations where the height of the boom arm 1 is selectable. It will be apparent to the reader that different lengths of support post 2 may be provided to achieve the same result. Optionally and particularly suited to livestock control barriers which can be moved from place to place and adaptable for different animals, including avian species, the enclosure 17 may be slidably movable along a support post 2 and locked into position to achieve the desired height of barrier boom arm 1. This arrangement is also suited to crowd control barriers where an enclosure can be attached to an existing post.

Reference is made above to use of the barrier and its adaptation for use beyond traditional applications, such as vehicle access control for car parks, railway crossings and crowd control, and the obvious extension to construction sites. Predominantly, the described uses are for situations where there is an enclosed resource, accommodation or facility to which access is controlled or otherwise regulated. However, there are many instances where it is important to monitor egress of individuals, including members of a workforce, cared-for community or simply to prevent pilfering by those having permitted access.

Reference is also made above to use of the barrier and its adaptation for use beyond livestock animals, such as cattle, sheep, pigs and equine species. The described uses are directed to animals that must be enclosed or otherwise prevented from escaping, however, there are many instances where it is important to prevent the ingress of other animals, including vermin and predators, which may kill livestock, consume foodstuffs intended for livestock and, just as critically, be significant vectors in the spreading of disease. The prevention or monitoring of vectors in the spreading of disease, for example, bovine tuberculosis carried by badgers and foot & mouth often carried on the footwear of individuals and in the tyre treads and wheel arches of vehicles is also of consideration.

Where the barrier is used with electrified enclosures for particularly chickens, turkeys, game birds and the like, the incidence of attack from predators, including foxes, can be attenuated. Adaptations to deal with potential incursions by larger predators such as coyotes, hyenas or dingoes (as appropriate to geographical location) are within the scope of the invention. Where the barrier is used with electrified enclosures for gated communities, manages estates or high-security premises, the provision of a barrier having monitoring, recording and alerting features enhances the utility of the barrier. Adaptations to deal with forced incursions or escapes (as appropriate to circumstances) are also within the scope of the invention.

The barrier boom arm 1 is coupled to and driven by the drive motor via the primary pivot disc 10 which rotates a barrier arm element holder 20 adapted to receive and secure the components making up the first arm element 21. Rotation of the holder 20 is communicated through the primary pivot disc 10 which is driven either directly via the drive shaft 7 of the motor or via reduction gears. In the arrangement illustrated in Figure 1 , the drive sprocket 9 is provided coaxially with the pivot axis A of the first arm element. At the other end of the first arm element, a second arm element 22 is pivotally coupled thereto and driven to rotate with respect to the first arm element by a transmission means (as described in more detail with reference to Figures 4a to 4d) having a drive cable 25 coupled between the primary disc 10 located on the pivot axis of the first arm and a driven pulley wheel located coaxially with the pivotal axis of the second arm 22.

The effective diameter of the driven pulley is half that of the primary pivot disc 10 located coaxially with the drive sprocket 9 and the pivot axis of the first arm element 21. To effect the movement of raising the barrier arm, the drive motor has an effective rotational limit of 90° to carry the first arm element from its horizontal closed position to its vertical open position and by virtue of the 2:1 ratio of the primary pivot disc 10 and the pulley, the 90° movement of the first arm element is translated into 180° relative movement of the second arm element. From an external perspective, the second arm 22 appears only to move through 90° between its horizontal closed position extending from the end of the first arm element and its vertical open position where it aligns with the first arm element. The driven pulley wheel is normally circular but may be presented as an ovoid so that, where required, the speed at which the second arm 22 extends is adjustable or made independent of the speed of closure of the first arm 21.

The barrier drive mechanism includes a spring to balance the weight of the boom in the closed position. As the barrier opening motion commences there is a high degree of self-balancing within the folding action that is not evident in fixed boom barriers.

Within the enclosure 17, the drive motor is controlled by an electronic control circuit 13 under management by a control system CPU and powered by a rechargeable battery 15. A recharging circuit is fed from an array of solar cells 29 which, in this embodiment, is mounted on a central longitudinal bar provided between the upper and lower tubes 21a,21b forming the first arm element 21. Where the requirement of the recharging circuit is low, the position of the array is not critical. Arrangements for the location of the array include mounted on a pole adjacent the support post 2 and may include tracking means to follow the path of the sun. Alternative recharging sources may be considered, depending on prevailing conditions. A micro wind turbine is a viable alternative in many areas.

Figure 1 illustrates a gate having a closed effective width W and a height H, however, the total height Ηχ of an open gate will not exceed H+l/2 W, as opposed to H + W for a fixed length boom arm.

Figure 2 illustrates a double span arrangement where two identical single barrier arrangements 1 are provided on each side of an access passageway. In the illustration shown in Figure 4d, the barrier arms 21 ,22 are shown at different intermediate positions to demonstrate that the locus defined by the distal end of the second barrier arm 22 is generally identical to the position defined by the distal ends when the barrier is closed, thereby giving an impression that the barrier arm ends open and close along a horizontal path, particularly when used in the paired arrangement of Figure 2. Advantageously, the motor controllers can be linked so as to ensure timely communication is made therebetween.

The significant advantage of the paired closure arrangement is the speed at which the central gap appears to close without having tip speeds which are likely to cause injury or damage. Due to the lightweight construction of the barrier, any impact will be easily deflected and the drive motor control will react accordingly. From the perspective of any person (whether walking or driving) or any animal adjacent or approaching the double span arrangement, the perception of two objects approaching laterally in a pincer movement will have an immediate deterrent impression significantly greater than that of a traditional raised boom barrier where the impression caused by a downwardly approaching barrier element is much delayed or may pass unnoticed until too late.

A transmitter TX located on a key fob or built-into the driver compartment of a vehicle is provided to activate the barrier remotely. A transmitter function can be incorporated into an application program (app) of a smartphone to utilise other communication paradigms. Alternative arrangements from the traditional pushbutton operation to audible or visual activation (such as that provided by a recognised sound waveform generated by a vehicle horn or optical input via the vehicle lights) are considered more fully below.

Figures 3a to 3e are a series of simplified schematic elevations of variations of a drive mechanism for imparting rotational movement to the pivot axis A of the first arm element 21.

In the variations of drive mechanism which follow, each drive motor 6 is positioned so that the drive shaft axis is transversely disposed to the pivot axis A of the first arm element 21. It will be appreciated that neither the position of the motor 6 or the relative positional relationship of the axis of the motor drive shaft 7 to the pivot axis A is of any real concern, the only factor relevant being the controlled rotation of a drive pin, wheel or arm to effect the movement of the arm element holder 20 which then carries the first arm element 21 in a restricted vertical plane.

Ideally, a motor having a low revolution per minute (RPM) rating is utilised to obviate the necessity for gearing. A low revving DC motor under electronic control produces the required speed without reduction. Effective reduction is produced by selecting the thread pitch of the threaded drive shaft 7.

In Figures 3a and 3b, a first variant of the drive mechanism comprises a DC drive motor 6 having a screw threaded, vertically disposed drive shaft 7 adapted to engage a correspondingly threaded boss 31 to effect a linear actuator. The boss 31 is fixed to a lever arm 32 to rotate a pivot shaft 33 disposed coaxially with the primary pivot axis A. According to the variant used, rotation of the lever arm 32 effects rotation of a primary pivot disc 10 and/or barrier arm element holder 20 (not shown), thereby moving the first arm element 21 between the closed position, illustrated in Figure 3a, and the open position, illustrated in Figure 3b. A gate counterweight spring 35 is secured to the lever arm 32 at one end and is fixed to an anchor point on a main support plate 36. The energiser 12 and motor controller 13 circuit boards, together with the motor and major actuation components are all mounted on the main support plate which acts as the primary fixing point over which weather proofing is provided before mounting within the enclosure 17. The drive motor housing is secured on the support plate 36 by means of a pivot pin 37 which allows an element of movement of the drive motor housing to accommodate lateral movement of the drive shaft 7 as the threaded boss rotates with respect to the pivot axis A. It will be appreciated that the lever arm 32 may be substituted by a pivot disc, such as the primary pivot disc 10 considered with regard to Figure 1 or as illustrated in the drive mechanism variant of Figure 3d. In either respect the efficient movement is the same, to drive the barrier arm tube holder 20 between its open and closed orientations.

The drive mechanism variants of Figures 3c and 3d utilise the same principles shown in the preceding drawings, however, instead of using a threaded boss 31 mounted at the lever arm 32, the linear actuation is effected by a different mechanism. In this arrangement, the DC motor drives a splined tubular element 40 which has an elongate slot 42 provided along its length. On the splined tube 40, there is arranged a pair of compression springs 44,45 adapted to act on a threaded pin 47 which is mounted to slide within the elongate slot 42. The pin acts on the threaded shaft 7 (which is no longer directly driven by the motor 6) to effect rotation of the lever arm 32 or of the primary pivot disc 10.

A sensor 49 coupled to the controller CPU detects movement of the drive shaft 7 which is not caused by the motor. If motion from the barrier arms moves the pin 47 within the limitations accommodated by the springs 44,45, it will be carried away from the sensor 49 which is mounted to the support plate 36. This movement may initiate a deterrent response if such a response has not already been initiated by earth detection (as will be detailed hereinafter).

Alternatively or additionally, a micro-switch arrangement is provided to detect movement of the barrier arm other than that caused by the drive motor. The micro-switch arrangement detects vertical movement caused by an animal, person or object (such as a branch) resting on the boom arm or an animal or person pushing upwardly in an attempt to raise the barrier or pass underneath the arm. The switch arrangement is ideally connected to a warning means or can initiate a small (ideally rapid) up and down movement of the barrier arm to startle the interfering person or animal or to dislodge a branch or other debris resting on the arm.

In some instances, where the interference detection circuit does not register the normally associated voltage drop to activate the deterrent means due to an animal is using the back of its neck to move the barrier arm upwardly, the switch arrangement will be used to initiate the deterrent delivery cycle.

A similar or associated switch is provided to detect unwarranted horizontal movement of the barrier boom arm and can be used similarly to startle or alert any animal or individual resting on or interfering with the gate. The horizontal deflection detection switch is ideally disposed between the drive mechanism enclosure and the support post. Activation of the horizontal deflection switch whether by vehicle, animal or person can initiate any one the warning or deterrent means referred to herein.

Figure 3 illustrates an alternative drive mechanism comprising a drive motor having a main shaft 7 carrying a worm gear 51 engaging a cog wheel 50 (acting in the manner of the primary pivot disc driven via the drive sprocket 9, as previously described with reference to Figure 1 ). The motor 6 is mounted on a hinge 52 so that the drive shaft 7, worm gear 51 and associated bearings 54 and compression springs 55,56 can be brought out of engagement with the cog wheel 50 when an excessive force is applied to the barrier arm 21. On the drive shaft 7, adjacent the worm gear, a pair of hard discs 57 are set at the same pitch angle as the threads on the worm gear so as to act as wear plates when the worm gear 51 is displaced. The vertical compression spring 56 acts with the hinged motor housing as an alternative to the shaft and bearing arrangement but can be used also in conjunction with the horizontal compression springs 55. The arrangement selected would shift wear to or from the driving threads on the worm gear 51 .

In a preferred arrangement, the worm gear is mounted on a splined or keyed drive shaft 7 secured at one end by the drive motor and by a bearing at its other end. The worm gear 51 can move or shuttle back and forth along the shaft against biasing force applied by the two opposed horizontal compression springs 55.

The cog wheel 50 is attached directly to a barrier boom pinion (coaxial with the pivot axis A) so that if the cog wheel is moved through 90° then the first arm element 21 of the barrier moves from horizontal to vertical. The cog wheel 50 is engaged by the worm gear 51 driven by the electric motor 6. Thus, the cog wheel and therefore the barrier boom can be held at any position by the electric motor which is under electronic control, which may determine exactly where the boom stops and can lock the barrier in any required position within the operational range.

When the motor is locked and the barrier arm is held in its open, closed or any intermediate position, if any upwardly or downwardly directed force is applied to the barrier arm, that force is transmitted via the cog wheel 50 to the worm gear 51. The worm gear absorbs the transmitted movement by sliding along the drive shaft 7 against the force exerted by the opposed horizontal compression springs 55. In any condition where the transmitted movement is so great as to overcome the compression springs and disengage the worm gear form the cog wheel, the barrier arm and cog wheel is allowed to move freely until the upwardly or downwardly directed force is removed. The compression spring will then drive the worm gear back along the splined or keyed drive shaft into engagement with the cog wheel. The movement will be directed by suitable electrical switches to cause the motor to turn the worm gear so that the cog wheel (and thus the barrier arm) is restored to the position within its normal operating range before the deflecting force was applied.

In a modified arrangement, the motor and drive shaft are hingedly mounted so that if excessive deflecting pressure is applied to the barrier boom, the worm gear will be disengaged from the cog wheel against the biasing force of a vertically disposed compression spring 56, so that the teeth of the cog wheel move over the corresponding teeth of the worm gear until the deflecting force is decreased or removed. The spring re-engages the worm gear and the cog wheel and the original position is re-established, as described above.

It will be appreciated by the skilled addressee that suitably hardened material is required to ensure longevity of the worm gear and cog wheel so that the corresponding teeth are capable of withstanding on-going engagement and disengagement of intermeshing gears. The barrier can recover or be manually recovered from a catastrophic event such as an impact in one or both of two planes. The spring or clutch mechanism associated with the drive motor described hereinabove allows for re-establishment of calibrated control of the barrier in the vertical plane. If the barrier is struck sufficiently hard to knock it horizontally out of the normal vertical plane, springs or torsion bar elements may be used to allow the barrier to be deflected without being damaged and move back to its original position once the deflecting force (or impediment) is removed. The horizontal return mechanism may be realised in a number of ways, such as those exemplified in Figures 5e and 5f below, without departing from the general disclosure of the invention. It will also be appreciated that excessive deflecting force will be a rare event and that damage to the drive mechanism caused thereby ought to be minimal.

Where the cog wheel 50 is selected having a 150mm diameter, with a worm drive pitch at 1.5 mm, it would take 1 19 turns to rotate the cog through 90°. This translates to a motor drive shaft speed of 950 rpm if the motion is accomplished in 5 seconds, which is possible with a standard DC motor. DC motor speeds are easily controllable to relatively low speeds. If a cog diameter of 175mm is used with a worm drive pitch of 1 mm, a motor speed of 1666 rpm produces the desired opening speed of around 5 seconds. Using a direct drive standard motor with the two horizontal compression springs acting as a buffer facilitates holding the gate at any selected position with motor lock out.

As with the other drive mechanisms, the primary advantage of this arrangement is that in a power-off or battery fail situation, the barrier maintains its position, unless pre-programmed to revert to another position.

Figures 4a to 4d are a series of front elevations of the barrier boom folding mechanism showing the movement between the extended closed position and the folded open position. The transmission means ensures rotation from the first drive sprocket mounted on the pivot axis of the first arm element is carried to the driven pulley wheel located on the drive coupling 60 at the opposite end thereof. The transmission means is effected by a belt or cable of wire or nylon is threaded through an upper tube ideally of a plastic or insulating material over an upper idler or tensioning roller, around the driven pulley and over a lower idler or tensioning roller to return to the drive sprocket through a lower tube. As the driven pulley is half the diameter of the drive sprocket, when the driven pulley is rotated, carrying the first arm element and driven pulley upwardly, the belt or cable transmits the movement and rotates the second arm element through an angle twice that of the first arm element.

Figure 4a is a reverse angle elevation of the drive coupling 60 which comprises two matching cast components, the first 62 having a pair of barrier arm tube receivers 62a,62b spaced so as to correspond to the tube holder assembly 20 driven via the motor, and the second 63 having a further pair of barrier arm tube receivers 63a,63b to carry the upper and lower tubes (not shown in Figure 4a) of the second arm element 22 of the barrier boom. The components are rotatable with respect to one another and have a central pivot bearing 65 mounted coaxially with a central driven pulley wheel 67. Upper and lower idler wheels (also known as jockey pulleys) 68 are used to direct the drive cable 25 from within the upper 21a and lower 21 b tubes of the first arm element 21.

As the driven rotation around the primary pivot axis A rotates the barrier arm holder 20, the cable 25 threaded through the upper and lower tubes 21a,21 b translates that rotation to the driven pulley wheel 67 of the drive coupling 60 so that, as the first arm element 21 is elevated, the second arm begins to fold. As shown in Figures 4b, 4c and 4d, the 90° angle subtended by the first arm 21 translates to 180° at the second arm, so that in the open position, the second arm aligns with the first arm.

The alternative drive mechanism illustrated in Figures 5a to 5d essentially comprises a modification of the mechanism shown in Figures 3a and 3b but including a crash clutch arrangement adapted to correct deflections of the barrier boom in a vertical plane outside the normal operating range.

The drive assembly includes a drive motor 6, mounted on a crash clutch plate 70 which includes a pair of pivot arms 72 connected to rollers 74 which ride along the edge of the clutch plate where scalloped regions are provided. As before, the drive motor 6 turns a threaded shaft 7 which operably moves a lever arm 32- via a threaded boss 31 fixed thereto. Linear motion is translated through a pivot shaft 33 to convey rotational motion to the barrier arm holder assembly 20 which includes receivers for the upper and lower tubes of the first arm element 21. The weight of the barrier boom is balanced by the counterweight spring 35 connected to the lever arm 32. Upper and lower shock absorbing springs 75,76 are provided on the drive shaft 7 on either side of the threaded boss 31.

As shown in Figure 5d, the clutch plate engagement rollers 74 are held in biased relation to the edge of the clutch plate 70 by at least one spring 78. In the neutral position shown, one roller opposes any upward movement and the other opposes any downward movement. It is only by exceeding a predetermined force (normally associated with the force required to break the barrier arm elements) that the spring biasing force will be overcome and the rollers move out of the scalloped area. A spring damper assembly may also be included in the drive assembly to absorb less intense vibrational forces and to smooth out the motor drive action and the transition between the open and closed barrier positions.

As referred to above, there are a number of ways to deal with deflective forces in the horizontal plane, however, in keeping with the feature of enhanced mobility of the barrier, the assemblies shown in Figures 5e and 5f are currently preferred but are ideally supplemented by electronic detection and deterrent. In the arrangement illustrated in Figure 5e, a spring steel rod 81 depends from the motor enclosure 17. Mounted on the support post 2 is a V-shaped rod holder 83 which will accommodate a predetermined amount of horizontal deflection of the barrier boom and return it to its central position in most scenarios. Similarly, in the arrangement illustrated in Figure 5f, an annular spring steel element 85 has a first upright 86 which engages the enclosure and a second inwardly facing component 87 adapted to engage a scalloped surface 89 provided on the support post 2. In either arrangement, a plastics material boss 90 may be provided to isolate the motor enclosure from the earthing point associated with the post.

Referring now to Figures 6a to 6c, which illustrate a block circuit diagram and a printed circuit board layout diagram showing the relative position of components used in the primary control system circuits associated with the drive control circuit, the power source recharging circuit, the interference detection and response delivery associated with the energiser circuits and an interface circuit for a user control or programming screen. Primary power is obtained from a battery pack (not illustrated) which is coupled to the circuit via a fixed regulator to establish a +12V rail. Integrated circuit (IC) regulators are used to establish 5V and 3V3 logic voltage rails. Further regulation via a IC rectifier circuit is provided for the microprocessor based central processing unit (CPU). The CPU is built around a ATMEGA 163P/AP chip.

In the interference detection and deterrent response energiser circuit, where the deterrent is an electric shock, an excitation circuit comprises a power transformer (EFD30) coupled to a high voltage doubler and resonance filter. This discharge voltage is accumulated in a first impulse reservoir and buck bypass circuit switched under CPU control. A second impulse reservoir is provided to accumulate a larger shock voltage which is released via a second impulse discharge switch.

Each tube of the first and second arm elements include electrically conductive components adapted to carry a pulse voltage whereby any animal or person who persistently interferes with the barrier will initiate a warning and/or deterrent means which may include receiving a disincentivising shock. The tubes may be provided with strips of conducting material or the tubes themselves may be formed of a conducting carbon fibre composite, aluminium, steel or other suitable conducting material. Additional conducting elements may be suspended from the lower tubes of the first and second arm elements to form a protective curtain to prevent ingress and egress of smaller animals, children or persistent adults ducking under the barrier arms. The conducting elements and, where applicable, the tubes themselves are electrically isolated from the drive mechanism, housing and support post. Advantageously, the excitation circuit is disconnected from the conductors when the barrier boom is elevated from the closed position. The means of delivery of a warning and/or deterrent, whether by sound (such as high intensity or low-frequency sound energy), visual output (including ultra-bright or strobed pulses) or by generation of a shock voltage will be at the choice of the skilled addressee, however, the means by which power dissipation is minimised during the operational cycle is distinguished. It is known that using typical energising circuits (such as those used on livestock electric fences), electrical energy supplied to the conducting parts dissipates over time, resulting in a constant demand to keep the shock voltage accumulators sufficiently elevated to provide a pre-set level shock when discharge is required. Normally, when the circuit is completed to ground by an inquisitive animal (or individual), capacitive discharge is triggered and a pulse voltage is delivered. By using a low-level monitoring current and accurately measuring the rate of discharge in normal operating conditions, the total overhead of the energising circuit can be minimised. This may be achieved by applying a low level of shock intended purely to detect a discharge to earth and thus the total energy cost can be reduced significantly. This is a detection voltage generated by the energiser circuit as part of interference detection and has no deterrent effect. When any voltage is applied to an insulated conducting object the charge does not dissipate immediately after it is applied. The greater the degree of insulation, the slower the dissipation. By measuring the rate of dissipation of the charge, it is possible to self-calibrate by setting a point at which the rate of dissipation indicates that the insulation has been broken down. In this system, that breakdown equates to an animal, person or vehicle touching the conducting surface of the gate. Modifications relating to the proximity of an animal, person or vehicle to deliver deterrent or warning output are within the scope of the invention. When the monitoring detects a rate of discharge indicating interference (that is, a short circuit to earth), a response is triggered. Figure 6d is a series of waveform responses where dissipation of a monitoring voltage firstly follows a normal characteristic for which no response is required. The second and third waveforms each initiate a response according to CPU analysis of the waveform.

The triggered response will often depend on the application to which the barrier is put. Where the barrier is located near a road or other location with easy human access or where crowd control is the primary aim of the barrier, an audible alarm might be sounded or a pre-recorded warning broadcast. Continued interference may activate a discharge voltage to the barrier tubes, commencing with a relatively low-level "kick" but building up to higher levels with further interference. Video monitoring may also be initiated at this stage. Audible and visual warnings and deterrents are also appropriate for vehicle access control as is the recordal of vehicle licence plates which may be processed using an optical character recognition algorithm.

In livestock applications, it is often beneficial to provide an initial low-level shock to deter an animal from investigating the passageway blocked by the barrier. With suitable warnings and adjustments of voltage applied and pulse duration, similar provisions can be made to protect against interference from people. When interference is detected by emitting a series of low level pulses at intervals of between 50ms and 1 second at a voltage of between 50 and 500 volts, known not to cause discomfort to an interfering animal or person, then depending on the livestock being constrained or on the likely age range or build of the individuals assumed to be interfering with the barrier, it is recommended that the first series of response pulses is not below 500V (as not being effective) and that a series of four or five 1200V pulses at 1 second intervals will achieve a desired result. The response pulse may be between 500V and 3000V and may consist of a combination of pulses of increasing intensity but will be a limited in total number. Once the response cycle outlined above is complete then the unit will revert back to the detection mode and pulse voltage. Once a shock response is required, the accumulators of the first and second high voltage reservoirs are charged (or topped-up) so that when discharge of the shock voltages are enabled, a shock voltage of between 500V and 1500V is used. Ideally, a first series of one or two 1000V pulses will course through the animal or subject individual. This can be followed by further shock voltages selected either from a second shock response range or by up to five additional pulses at 1 second intervals. If the detection circuit indicates that the animal or subject individual has continued to interfere, the second shock response range of between 1000V and 3000V is used. Current UK regulations stipulate that no more than 1 pulse per second is applied in this range and accordingly this voltage range or pulse frequency can be adjusted for humans. Taking an elevated voltage of 2000V, a first pulse may be considered sufficient or may be followed by up to five subsequent pulses at a frequency of no more than 1 per second. The detection mode is then restored and the cycle repeated if interference continues. After a number of cycles, a fault condition may be established and, depending on the functions available, an audible alarm (to frighten a curious animal or to alert an individual of the risk of shock) and/or a video relay may be indicated. The functions and response are normally preprogrammed into the controller CPU which determines actions based on sensor input and feedback or according to an algorithm that uses information collected from the energiser circuit. In a modification to the arm element tubes, separate conductors may be provided on each individual tube to distinguish on which side of the barrier the interference takes place. The detection circuit will determine the source of the short circuit and provide the CPU with the appropriate signal. The CPU then triggers the appropriate response. In a further adaptation, a conductor located along the underside of the lower tube (or lower edge of a boom arm element) may be specifically utilised or monitored for interference characteristics of an animal using the back of its neck to raise the barrier. In such circumstances, a shock in the order of 6000V can be delivered if interference persists, as in many instances lower voltages will not have the required deterrent effect. This higher voltage may also be used when the detection circuit is superseded by a vertical deflection actuator switch, as referenced above. The detection pulse may comprise multiple short pulses, for example, five over a l OOmS period. The response pulse may escalate at a different rate and to a different level. The detection circuit measures the rate of deterioration of a predetermined number of detection pulses and uses this information as the basis for any calculation to determine interference, whether continuously, at fixed intervals or on a pre-programmed schedule of detection pulses. This enables the detection circuit to calibrate the trigger point for rate deterioration that initiates a response cycle allowing it to adapt the changes in external conditions which may affect the manner in which the discharge of shock level voltages is interpreted.

Figure 7 is a series of diagrammatic representations of a user interface touch- sensitive screen which may also be used as a programmable interface for the primary control circuits, for setting barrier speed, timing intervals, energising circuit response type or intensity level and pulse timing amongst others. In the first screen, which displays on start-up or after an energy-saving interval, a system trade mark, company logo or selected screen saver is displayed. A numeric keypad is presented to the user either to enter a personal identification number for security purposes or selects a number corresponding to the barrier through which access is required.

The two coloured buttons are used for accessing a programming menu (not shown) and can be pressed simultaneously to pair a controller with a barrier drive circuit. Once pairing is established the coloured buttons merge to indicate the programming mode where programming is conducted via the numerical keypad only. Holding the pair icon reverts the screen to the normal keypad arrangement.

On the next screen, the current position of the normally closed barrier is displayed together with three status icons which will be expanded on in more detail below. To open the barrier, the user presses the pictogram of the gate. When the barrier is raised the pictogram changes to a representation of an elevated and folded barrier together with a HOLD button which may be programmed to ensure the barrier remains open until the HOLD button is pressed to release the barrier (at which time it may change colour or flash) or have a pre-programmed period after which the gate automatically closes unless the button is touched/pressed. Flashing of the button may indicate a change or transition in barrier position or as a warning of the elapsing of the pre-programmed delay period. Where there is a requirement for a vehicle or vehicle and trailer to be stationary within the protected access or passageway, the HOLD button may be utilised as an electronic lock.

Referring now to the status icons, each of which has a separate sub-screen allocated to it, as shown. The first sub-screen illustrates the status of battery pack charging and current capacity. Where a solar array is utilised, the output of the array is given, either instantaneously or as an overall indication of system demand against charging capacity. This indication is of particular relevance during continuous low-light conditions (including winter) or where a micro wind turbine is used as the recharging source, the average wind speed as an overall indication of its appropriateness as a recharging source given prevailing conditions. Additionally, a record of temperature is kept and may be displayed as current, average, highest and lowest recorded. As with all of the sub-screens, a MAIN

SCREEN return icon is provided. The central icon expands to the second sub- screen to indicate an "interference count". This is particularly relevant where the barrier is used for security, stock and livestock applications. As detailed above, the barrier boom arms include conductors connected to a detection circuit and/or an energising circuit which can be utilised to record the incidence and nature of any interference of the barrier boom. An interference count in itself may be useful, however, interference when correlated to time builds a more accurate interpretation of the nature of the interference. The detection circuit may also be integrated with a surveillance system having a video recording capability. Additionally, a "last time of interference" indicator should be distinguished from the last time of legitimate access entry or exit. The right hand icon on the main screen indicates the status of the detection circuit and energising circuit (or alarm/monitoring circuit) and opens the third sub-screen. Three status conditions are available, the first indicating that both circuits are on, the second indicating that the detection circuit is enabled but that the energising circuit (or alarm/monitoring circuit) is disabled and finally, the third icon indicates that the detection circuit is enabled but that the energising circuit (or alarm/monitoring circuit) is disabled.

Summarising the hardware provided against generated inputs and outputs, there is provided a barrier system which comprises a battery pack having a nominal voltage selected within the range 6 to 24V. Normally, a 12V battery pack, supplemented by a solar panel, is used to drive a barrier boom motor via a controller mounted on a main PCB. Additional hardware includes an energiser circuit, an interference detector and a proximity detector. A remote control actuator is optionally provided as an alternative to push-button activation and may be presented as a keypad, conveniently with a touch sensitive screen.

With remote actuation, a low power RF signal may be used as an alternative to an ultrasonic, Bluetooth or IR input. Basic controller response indicates that the barrier arm should be raised but power demand detection may indicate an obstruction. Where an incremental increase in motor current does not generate a peak in the demand detection circuit, the arm is raised. Where further obstruction is detected, an alarm state is generated. A "state of system" display may be provided on the barrier and implemented as simply as a tri-coloured LED or by a simple LED array.

The pressure sensor and interference sensor circuit may be coupled to provide log or status information. Where the interference sensor circuit is disabled, the presence sensor detects whether a vehicle is within the access passageway and disables the "barrier down" instruction and/or generates an alarm signal.

Where barriers are provided in pairs (or in sets of four at a railway crossing), each barrier is capable of communicating status information to a paired barrier. This means that barriers may act together or in timed relationship to effect better and more flexible access control. Positioning of paired gates may thus be synchronised.

A recharging circuit connected to the battery pack monitors the solar panel (or wind turbine) voltage output to ensure there is no overcharging of the battery pack. The operator may prescribe whether the calculation of average power consumption against power replenishment is conducted over 1 hour or 1 week to obtain a positive or negative indication of capacity. Additional functionality includes monitoring hours (and intensity) of daylight above a threshold level. This may be coupled to an ambient temperature sensor to display easily obtainable weather data and to create a log for optimising the recharging source, for example, by increasing the size of the solar panel, repositioning it or installing tracking means. Where a wind turbine is used, its elevation or output rating may have to be reassessed if recharging output is insufficient, too irregular or cannot meet peak demand.

The barrier energiser circuit, which is installed to be independent from adjacent electrified fences, for example, has a controlled and regulated output based on the nature and duration of any sensed interference. Standard shock voltages may be available, however, power consumption (and therefore battery pack and recharging source capacity) may be reduced significantly by intelligent control, as described in detail hereinabove.

Where the gate is a part of an existing electric fence system then it may make use of that system instead of its own. This may be expedient where the animals are very used to electric fences or where the gate is substituting for a standard electric fence gate. As will be appreciated from the foregoing, a high level of monitoring and remote control may be achieved with the barriers of the invention, allowing for enhanced safety, security and recordal of events. Utilisation of 2G, 3G, 4G and associated cellular telephone networks provides access to data and live video streaming where required without a significant power consumption overhead.

Thus, barrier activation may be initiated in any number of ways depending on system requirements or on the requirements of the owner/operator. Where access to an enclosure needs to be secure but easily accessible to authorised personnel or vehicles, remote activation is ideally initiated by proximity of the person or a vehicle carrying an RF transmitter. Authentication may be made via a backup signal which may be ultrasonic or infrared based. As indicated above, a touch screen keypad is optionally provided so that a PIN (Personal Identification Number) may be used. Additionally, where a computer network card (TCP/IP), mobile telephony or Wi-Fi Internet connectivity is provided, control of the barrier and access to its security and monitoring functions can be enabled from anywhere with similar wireless or internet connections.

In an alternative arrangement, the barrier or each barrier (where paired) may be activated by generating a signal from a vehicle. By utilising a vehicle horn, a recognisable and distinguishable waveform can be detected and barrier activation initiated. When produced by an adjacent, static vehicle, a vehicle horn will produce a substantially square wave signal. Where a series of two or three horn blasts over a threshold level of, for example, +75dB is detected, a logic circuit will determine the profile of the waveform (possibly by comparing the leading and trailing edge slopes of the waveform) and, where consistent with predetermined parameters, will open the barrier. Signal comparisons can be used to measure length, amplitude and any variation in frequency (notably to distinguish from passing traffic) to determine qualifying signals. A similar adaptation may be devised for utilising optical signalling from vehicle lights.

It will be appreciated by the skilled addressee that the barrier of the invention addresses many of the short-comings of existing barrier systems and provided a single solution that is adaptable to many common or situation specific requirements. It will also be appreciated that by its nature the barrier may be independent of any other installed system, is self-powered and can easily be integrated into any monitoring system or establish one of its own. As the barrier, power supply and controller is totally self-contained, it is easily transportable form one site to another. Advantageously, a movable support and support anchor may be provided, so that the barrier may be provided as ready solution or as an interim replacement for a failed or damaged installation.

Due to the selection of components and the use of electronic control for the energising circuit (which is ideally coupled to the control system CPU), the power requirements of the barrier are minimised. In a "sleep mode", the current draw can be reduced to less than 5mA (the fencer unit is 0.25mA possibly but the radio unit and solar control unit take this up somewhat). In most installations, the battery pack can be reduced to a single, low value, 7 Ah or less, 12V sealed unit. It will of course be understood that the invention is not limited to the specific details described herein, which are given by way of example only, and that various modifications and alterations are possible within the scope of the appended claims.